The field of the present invention relates to packaging of thin rectangular items. In particular, a packaging article is disclosed for providing support of thin, fragile rectangular parts, e.g., optical components, of various sizes by contact with only the edges of the parts, so as to prevent damage or contamination of the faces of the parts by contact with the packaging article.
In a package employed for transporting a fragile or delicate item or part, it is typically preferred that the item be held immobile. If contact with surfaces of the part can soil, damage, or otherwise degrade the item, the item is preferably held immobile by contact with only its edges.
In the case of thick parts, conventional packages have been developed that utilize edge contact to hold the part immobile while touching only edges. For example, a plastic sheet can be vacuum molded so as to exhibit a depression (of a suitable shape, such as a rectangular slot) that is slightly larger than the part to be held. The sides of the depression can slope down at less than 90 degrees so that the closed bottom of the depression is slightly smaller than the piece to be held. The thick part is inserted into the depression until friction with the sloped wall (against the part's sides) holds it securely immobilized. By creating one or more such molded depressions on a sheet of plastic and molding the edges of the plastic sheet to fit within an enclosure such as a box (plastic, paper or cardboard, or other suitable box material), a useful package can be provided that holds sensitive parts immobile and makes contact with only the edges of the parts. Typically, the edges of the molded sheet would be shaped so as to hold the depressions above the bottom of the box.
Such a packaging arrangement, which is in use currently, has several disadvantages. First, the depressions involved must have at least one dimension nearly identical to the parts to be packaged. As a result, it may be necessary to inventory many different packaging articles in order to accommodate an array of part sizes. Second, the depression packaging approach does not work well for thin parts. Thin parts are prone to rotating or tilting within the depression and losing frictional engagement with its sloped side walls. Should this happen, the part is no longer immobilized and one or more of its surfaces can come into contact with the packaging material, causing damage, contamination, or other degradation.